1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 */ 19 package org.eclipse.aether.util.graph.visitor; 20 21 import org.eclipse.aether.graph.DependencyNode; 22 23 /** 24 * Generates a sequence of dependency nodes from a dependency graph by traversing the graph in postorder. This visitor 25 * visits each node exactly once regardless how many paths within the dependency graph lead to the node such that the 26 * resulting node sequence is free of duplicates. 27 * <p> 28 * The newer classes {@link AbstractDependencyNodeConsumerVisitor} and {@link NodeListGenerator} offer 29 * similar capabilities but are pluggable. Use of this class, while not deprecated, is discouraged. This class 30 * is not used in Resolver and is kept only for backward compatibility reasons. 31 * 32 * @see PostorderDependencyNodeConsumerVisitor 33 * @see NodeListGenerator 34 * 35 * @deprecated See {@link PostorderDependencyNodeConsumerVisitor} that is more versatile. 36 */ 37 @Deprecated 38 public final class PostorderNodeListGenerator extends AbstractDepthFirstNodeListGenerator { 39 40 private final Stack<Boolean> visits; 41 42 /** 43 * Creates a new postorder list generator. 44 */ 45 public PostorderNodeListGenerator() { 46 visits = new Stack<>(); 47 } 48 49 @Override 50 public boolean visitEnter(DependencyNode node) { 51 boolean visited = !setVisited(node); 52 53 visits.push(visited); 54 55 return !visited; 56 } 57 58 @Override 59 public boolean visitLeave(DependencyNode node) { 60 Boolean visited = visits.pop(); 61 62 if (visited) { 63 return true; 64 } 65 66 if (node.getDependency() != null) { 67 nodes.add(node); 68 } 69 70 return true; 71 } 72 }